Walgreens plans to open full-service doctors’ offices in hundreds of its stores across the U.S. during the next five years.It’s part of a bigger effort by the drugstore chain to become a one-stop shop for health care.Walgreens Boots Alliance is partnering with health care company VillageMD to create the 500 to 700 primary care clinics. During the next three years, Walgreens will invest $1 billion